Significance of the Presence of Bovine Milk β-Glucuronidase in Mastitis Detection

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Abstract
The presence of .beta.-glucuronidase enzyme in bovine milk was related both to the existence of major and minor pathogens and to somatic cell counts. The detection of this enzyme in whole milk was made possible by the use of p-nitrophenyl-.beta.-glucuronide as a substrate. This detection allowed us to determine abnormal udder secretions with a high degree of specificity and sensitivity. The particular method of enzyme determination was considered important for mastitis detection because .beta.-D-glucuronidase, the most significant enzyme in inflammatory processes, is released selectively. The relationship between enzyme, presence of pathogens, and somatic cell counts was established in 220 milk samples obtained at random from individual quarters of apparently healthy udders of cows from four local dairy farm (Santiago del Estero and Tucuman, Argentina). Four of these samples were from cows of recent parturition and two from cows with severe clinical mastitis. Only 17% of the milk samples were normal with somatic cell counts 500,000 cells/ml or less. This ratio is the usual one throughout the area, and the remaining 83% showed higher somatic cell counts. Taking the latter as 100%, the presence of .beta.-glucuronidase and the positive bacteriological analyses represented 76 and 74%, respectively.